400821587946 has 80 divisors (see below), whose sum is σ = 967803334344. Its totient is φ = 123255945216.

The previous prime is 400821587927. The next prime is 400821587951. The reversal of 400821587946 is 649785128004.

It is a happy number.

400821587946 is a `hidden beast` number, since 400 + 82 + 1 + 58 + 79 + 46 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 380305322721 + 20516265225 = 616689^2 + 143235^2 .

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 400821587892 and 400821587901.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3517806 + ... + 3629958.

Almost surely, 2^400821587946 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400821587946, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (483901667172).

400821587946 is an abundant number, since it is smaller than the sum of its proper divisors (566981746398).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

400821587946 is a wasteful number, since it uses less digits than its factorization.

400821587946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113877 (or 113868 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 400821587946 in words is "four hundred billion, eight hundred twenty-one million, five hundred eighty-seven thousand, nine hundred forty-six".